alzheimer and aging

A recent study at the University of California-San Francisco shows that with age, the ability to "multitask" in the brain decreases.

Using MRI, the medical team compared two groups of healthy people. The former had an average age of 24.5 years and the second 69 years. Both groups were invited to see and remember a scene from their natural environment for 14 seconds. In the middle of this year, an interrupt has occurred: a face appeared on the screen, and participants were asked to identify their sex and age. Then they were asked to recall again the original scene.

Result: the elderly have more difficulty than young to remember the original image.
The brain scans showed that younger subjects were able to quickly disengage from the original image, and then respond to the interruption refocus their memory again on the original scene. Seniors for their part were much more difficult to manage the transition from one scene to another.

As noted by the researchers, the problem is not really that of memory, it is rather an impaired ability to play between different networks of neurons. It is the ability to switch from a neural network dedicated to attention, another dedicated to the memory that is involved.